South Island’s new weather radar gets a home

The Government has announced the site has been chosen for a new radar for the top of the South Island, to address a black spot in the country’s weather forecasting coverage.

The project has been fast-tracked by the Government with funding of up to $5 million, following the severe storms and flooding last July.

South Island Minister James Meager said the Nelson Tasman region had limited radar coverage as it relied largely on the Wellington radar, which could not adequately monitor parts of northwest Tasman.

“The region has experienced several high-impact flooding events in recent years, including five states of emergency since 2011. The new radar will make a huge difference in better preparing communities for future disasters.”

The radar will be located near Horoirangi Peak, about 15km northeast of Nelson City at 630m above sea level. It is expected to be operational by mid-2027.

MetService will install and operate the radar, with ongoing annual operating costs expected to be around $260,000. It will feature modern Doppler dual-polarisation technology, which provides more accurate rainfall estimates and enhanced weather monitoring capability.

MetService general manager of observing systems Kevin Alder said the Prime Minister’s announcement last July that the Government would fund a radar for the region (came as “a bit of a surprise”), and a lot of work had gone on since then to make it happen.

He said MetService had evaluated around 10 sites on the eastern hills around Nelson and the central hills around Moutere and over towards Motueka and the Kahurangi National Park, and the Horoirangi site was chosen because it was at the right altitude and had landowners willing to host the infrastructure.

Alder said the key challenges were finding a location that was not too high, as the radar would miss the weather and not too low where it would be blocked by mountains and ranges.

He said the new radar would provide hydrologists, Civil Defence and the community with real-time information they could trust. The radar would provide information about precipitation, wind fields, thunderstorms and hail.

“At the moment the coverage from the Wellington radar doesn’t have the level of detail that is required, so we’re going to see an increase in confidence in their ability to make decisions for the regions.

“It’s about making sure communities are well informed and able to respond in a timely manner because we’re all here to protect life and property.”

Andrew Stephens of Ngāti Tama ki Te Waipounamu said the Horoirangi maunga and surrounding area was very dear to iwi.

His great-grandmother Hūria Mātenga, her husband and several other Māori had helped to rescue people off the American-built brigantine Delaware, when it was caught in a storm and wrecked on the rocks off the coast of nearby Whakapuaka in 1863.

“It’s quite apt that the knowledge we will gather prior to an event will be available from this maunga,” he said.

“It’s going to save lives. It’s going to help industry and it’s going to help the community.”

Tasman Mayor Tim King said things had moved relatively quickly, since the Government announced it would fund the radar after last year’s floods and it would be another “very valuable tool” when it came to preparing for floods.

“We already invest significantly, between Nelson and Tasman, in both the rain-gauging network and the river monitoring network. All of that carries a significant risk because as we found during the June-July events, they can be damaged, destroyed and become inoperable,” he said.

“This provides a real degree of resilience because it’s separated from the actual weather event itself.”

King said while it would provide more data, people were still needed on the ground to interpret the information that came in from different sources, in order to provide advice to incident controllers and decision makers.

Nelson Mayor Nick Smith said it was a relief to know the radar would soon be up and running, as the region had dealt with “too many emergency events” over the last decade.

“It’s a really difficult call as to whether you’re going to evacuate people, not wanting to put people out and declare a state of emergency and not having adequate information to be able to make those big calls was one of the reasons that both myself, Tim King and others were such strong advocates for getting the additional technology.”

But Smith said there was no “single magic bullet” to manage the risks associated with storm events and climate change.

“There will always be a level of risk, but what we can do with hand-on-heart is say that this new equipment will enable us to better manage those risks in the future, it will save lives and it will make our community more resilient.”

Retired Tasman District Council hydrologist Martin Doyle said he had campaigned for a weather radar to be installed in the region since 2010 (when there was a massive flood in the Aorere River) and hydrology staff were left without knowledge of where the rainfall had come from.

He said there were many small river catchments across the region and it was impossible to have a rain gauge in each one.

“Having the ability to see where rain is falling in a very confined area is going to be very beneficial for hydrologists but also the community members out there can do their own analysis and make their own decisions by having that radar.”

The information provided by the radar would enable Civil Defence and Emergency Management to make better decisions, but it would also allow the community to make better informed decisions to keep themselves safe.